.kuang{
  width: 600px;
  height: 500px;
  border: 1px #ccc solid;
  margin: 20px auto;
  display: flex;

}
.left-nav{
  width: 100px;
  height: 100%;
  border-right: 1px #ccc solid;
}
.left-nav a{
  display: block;
  height: 20px;
  line-height: 20px;
  text-align: center;
  background: #aaa;
  color: white;
}
.right-content{
  width: 500px;
  height: 100%;
}